Enhanced antistatic additives for hydrocarbon fuels &amp; solvents

ABSTRACT

Described herein are enhanced performance of antistatic additive compositions for hydrocarbon fuels, the compositions comprising olefin-sulfur dioxide copolymers in combination with polymeric polyamines prepared using an ortho-xylene solvent.

FIELD OF THE INVENTION

This invention concerns an improved two-component antistatic additivefor hydrocarbon fuels and solvents to render them electricallyconductive. One component is an olefin-sulfur dioxide copolymer(polysulfone copolymer) prepared in orthoxylene, and the other componentis a particular polymeric polyamine.

BACKGROUND OF THE INVENTION

Hydrocarbon fuels normally are very poor conductors of electricity.Electrical charges, therefore, tend to accumulate in the fuel and can bedischarged as sparks thus creating the danger of an explosion or fireshould such charges ignite hydrocarbon-air admixtures that may bepresent.

Numerous materials have been suggested in the art to increase theelectrical conductivity of hydrocarbon fuels. Suggested materialsinclude two-component additives where one component is a polysulfone andthe other is a quaternary ammonium compound. Another suggestedtwo-component additive comprises polysulfone as one component andpolyvalent metal organic compounds of metals having an atomic number offrom 22 to 29 as the other component.

An important aspect is the solvent used for the polymerization of thepoly Sulfone component. Typically, solvents such as benzene, toluene, etal. have been employed. These solvents contain impurities which mayresult in a potentially toxic situation. Thus, there is a clear need toemploy a safer solvent.

BRIEF SUMMARY OF THE INVENTION

The two-component antistatic additives of this invention arecharacterized by being highly effective at low levels of usage and bybeing ashless upon burning. These two-component antistatic additives areso efficient that even at relatively low concentrations they provide thedesired conductivity (measured in picomhos per meter, orpicoSiemens/meter) in nearly all hydro-carbon fuels. This performance isenhanced when the solvent for polymerization of the olefin and sulfurdioxide is ortho-xylene.

In the antistatic additive of this invention wherein the components arepresented in a weight ratio of 100:1 to 1:100, and wherein one componentis a polysulfone copolymer prepared in ortho-xylene solvent comprisingabout 50 mol percent of units from sulfur dioxide, about 40 to 50 molpercent of units derived from one or more 1-alkenes each having fromabout 4 to 24 carbon atoms, and from about 0 to 10 mol percent of unitsderived from an olefinic compound having the formula ACH═CHB wherein Ais a group having the formula —(C_(x)H_(2x))—COOH wherein x is from 1 toabout 23, and B is hydrogen or carboxyl, with the proviso that when B iscarboxyl, x is 1, and wherein A and B together can be a dicarboxylicanhydride group, the antistatic composition comprises, in combinationwith said polysulfone component, a polymeric polyamide of the formula

R¹ is an aliphatic hydrocarbyl group of 4 to 24 carbon atoms,

R² is an alkylene group of 2 to 6 carbon atoms,

R is R¹, or, an N-aliphatic hydrocarbyl alkylene group of the formulaR¹NHR²,

-   -   a is an integer of 0 to 20,    -   b is an integer of 0 to 20,    -   c is an integer of 0 to 20, and    -   x is an integer of 1 to 2,

with the proviso that when R is R¹ then a is an integer of 2 to 20 andb=c=0, and when R is R¹ NH—R² then a is 0 and b+c is an integer of 2 to20.

Particular embodiments of this invention are those wherein thepolysulfone is composed solely of units derived from sulfur dioxide andunits derived from at least one 1-alkene of from 4 to 24 carbon atoms. Aparticular embodiment is that wherein the 1-alkene is 1-decene and isprepared in an ortho-xylene solvent.

One embodiment, with reference to the polyamine component, is that whereR═R¹, wherein R¹ is an aliphatic hydrocarbyl group of 4 to 24 carbonatoms, especially where R¹ is the aliphatic hydrocarbyl group oftallowamine.

Also, with reference to the polyamine component, are embodiments where Ris R¹NHR², wherein R¹ is an aliphatic hydrocarbyl group of 8 to 22carbon atoms and R² is an alkylene group of 3 carbon atoms, especiallywhere R¹ is the aliphatic hydrocarbyl group of tallowamine.

In one aspect of the invention, a polysulfone copolymer of the inventionis 1-decene polysulfone having an molecular weight in the range of10,000 to 1,500,000 amu and in a particular aspect, the polymericpolyamine is the polymeric 1:1.25 mol ratio reaction product ofN-tallow-1,3-diaminopropane with epichlorohydrin.

The weight ratio of polysulfone copolymer to polymeric polyamine in theinvention composition ranges from about 100:1 to 1:100, in one aspectfrom about 50:1 to 1:1, and in another aspect from about 20:1 to 1:1.

This invention also concerns the two-component additive as heretoforedescribed together with a strong acid (oil-soluble sulfonic acid issuitable). Thus, a polyamine-sulfonic acid salt will be formed which hasan improved resistance to precipitate-formation during long storageperiods. This invention also concerns the additives in concentrate formin a solvent. One composition containing the antistatic additive, anacid to enhance precipitate-free storability, and a solvent, comprises,based on total weight:

-   -   i. from about 1 to 50 percent of the polysulfone, prepared in an        ortho xylene solvent,    -   ii. from about 1 to 50 percent of the polymeric polyamine,    -   iii. from about 1 to 30 percent of oil-soluble sulfonic acid,        and    -   iv. from about 3 to 97 percent of solvent.

A suitable sulfonic acid (iii) is mono and di sulfonates of alkybenzenes, and in one aspect is dodecylbenzene sulfonic acid, ordinonylnaphthyl sulfonic acid.

This invention also concerns a composition comprising a liquidhydrocarbon fuel boiling in the range of from about 20° to 375° C., andfrom about 0.01 ppm to 40 ppm of the two-component polysulfone-polyamineantistatic additive composition and the additive composition stabilizedwith a strong acid as described herein. Although more than 40 ppm of theadditive can be used, no significant benefit is thereby derived. Theadditive composition can also be used in solvents, oils, and othermixtures such as paints and other formulations where improvedconductivity is desired.

Certain co-additives which are known to provide good initial electricalconductivity in cooperation with the polysulfone copolymer component canalso be included in the present invention composition. Included arequaternary ammonium compounds which are more fully described incoassigned U.S. Pat. No. 3,811,848 (the entire teaching of which isherein incorporated in its entirety by reference).

It has been found that improved three-component antistatic compositionscan be obtained by combining the polymeric polyamine described hereinwith a two-component antistatic additive comprising:

(i) a polysulfone copolymer prepared in ortho-xylene comprising about 50mol percent of units derived from sulfur dioxide from about 40 to 50 molpercent of units derived from 1-alkene of 4 to 24 carbon atoms and from0 to about 10 mol percent of units derived from an olefin having theformula

whereinA is a group having the formula —(C_(x)H_(2x))—COOH wherein x is fromabout 0 to about 17, and B is hydrogen or carboxyl, with the provisothat when B is carboxyl, x is 0, and wherein A and B together can be adicarboxylic anhydride group and

(ii) a quaternary ammonium compound having the formula:

whereinAlk¹ and Alk² are the same or different alkyl groups having from 1 to 22carbon atoms, Alk³ is selected from the group consisting of alkyl groupsof 1 to 22 carbon atoms and

where Alk³ is hydrogen or methyl and n is 1 to 20,Alk⁴ is selected from the group consisting of (a) an alkyl group having1 to 22 carbon atoms, (b) an aralkyl group having from 7 to 22 carbonatoms, (c) a

group as defined above, (d) a

group whereinAlk⁶ and Alk⁷ are the same or different alkyl groups having from 11 to19 carbon atoms, and (e) an —Alk⁸—CO₂ group wherein Alk⁸ is ahydrocarbyl group having from 1 to 17 carbon atoms, with the provisothat when Alk¹, Alk², Alk³ and Alk⁴ are each alkyl groups, at least oneof them is an alkyl group having at least 8 carbon atoms,

A is an anion,

z is 0 or 1, z is 0 when Alk⁴ is (d) or (e), and

y is at least 1, y is equal to the ionic valence of anion A when z is 1.

The ratio of the components are such that for each part of polysulfonethere is 0.01 to 100 parts of each of the polymeric polyamine and thequaternary ammonium compound.

A suitable quaternary ammonium compound is dicocodimethyl ammoniumnitrite wherein “coco” refers to a mixture of C₈ to C₁₈ alkyl radicalsof cocoamine. The quaternary ammonium compound can be present in theamounts of from about 1 part to 25 parts per 100 parts of polysulfonecopolymer. The presence of a quaternary ammonium compound furtherenhances the electrical conductivity of the present inventioncomposition in many hydrocarbon fuels and maintains the compositionash-free.

Another embodiment of the present invention is directed to a fuel oilcomposition. This fuel composition can comprise a suitable fuelcomponent and a suitable additive component. In one aspect, thecomposition comprises from about 99.99% fuel and about 0.01% of additiveto about 99.9999% fuel to about 0.0001% of additive. A suitable additiveincludes those described herein.

The term “hydrocarbyl” employed herein refers to straight andbranched-chain groups containing only carbon and hydrogen. Such groupscan be saturated, unsaturated or aromatic.

For a better understanding of the present invention, together with otherand further objects thereof, reference is made to the accompanyingdrawings and detailed description and its scope will be pointed out inthe appended claims.

DETAILED DESCRIPTION OF THE INVENTION

The Polysulfones:

The polysulfone compolymers often designated as olefin-sulfur dioxidecopolymer, olefin polysulfones, or poly(olefin sulfone) are polymerswherein the structure is considered to be that of alternating copolymersof the olefins and sulfur dioxide, having a one-to-one molar ratio ofthe comonomers with the olefins in head to tail arrangement. Thepolysulfones used in this invention are readily prepared by the methodsknown in the art (cf. Encyclopedia of Polymer Science and TechnologyVol. 9, Interscience Publishers, page 460 etc, the entire teaching ofwhich is incorporated herein by reference).

The weight average molecular weights of the polysulfones are in therange from about 10,000 to about 1,500,000, in one aspect the range isfrom about 50,000 to about 900,000, and in another aspect the molecularweights range from about 100,000 to about 500,000. Olefin polysulfoneswhose molecular weights are below about 10,000, while effective inincreasing conductivity in hydrocarbon fuels, do not increase theconductivity values as much as olefin polysulfones of higher molecularweights. Olefin polysulfones whose molecular weights are above about1,500,000 are difficult to produce and are more difficult to handle.

The molecular weights of the olefin polysulfones can be determined byany of the well-known methods, such as the light scattering method. Itis generally more convenient, however, to determine the inherentviscosity of the polymer to derive the approximate molecular weightrange of the polysulfones therefrom. Inherent viscosity is defined asη_(inh)=ln.η_(rel)/C wherein In is the natural logarithm, η_(rel) is arelative viscosity, i.e., ratio of the viscosity of the polymer solutionto the viscosity of the polymer solvent and C is concentration ofpolymer g/100 mL. The units of inherent viscosity are deciliters pergram (dl/g). The inherent viscosities of olefin poly-sulfones areconveniently measured in toluene at 30° C. as 0.5 weight percentsolutions. It has been found by comparison with molecular weightdeterminations that polysulfones with inherent viscosities of betweenabout 0.1 dl/g to 1.6 dl/g correspond to weight average molecularweights in the range of about 50,000 to 900,000.

The control of the molecular weights of the olefin polysulfones in thedesired range is readily accomplished by those skilled in the art ofpolymer science by controlling the polymerization conditions such as theamount of initiator used, polymerization temperature and the like or byusing molecular weight modifiers such as dodecyl mercaptan. The amountof molecular weight modifier required to obtain the desired molecularweight range will depend upon the particular 1-olefin being polymerizedwith sulfur dioxide, and can be determined easily with few experiments.Generally, the amount of modifier, such as dodecyl mercaptan, used toobtain the molecular weights in the range of 50,000 to 900,000 is in therange of up to about 0.007 mole per mole of 1-olefin.

The 1-alkenes useful for the preparation of the polysulfones areavailable commercially as pure or mixed olefins from petroleum crackingprocesses or from the polymerization of ethylene to a low degree.Included, but not limited to, are 1-hexene, 1-heptene, 1-octene,1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene,1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonodecene,1-eicosene, 1-heneicosene, 1-docosene, 1-tricosene and 1-tetracosene.Poly unsaturated olefins such as butadiene and its analogs, and branchedolefins and internal olefins are also utilizeable in the invention.Although branched-chain alkenes are useful, the straight-chain 1-alkenesare also useful whether pure or in admixture with other straight-chain1-alkenes.

When the polysulfone copolymer contains up to 10 mol percent of theolefin AHC═CHB, as defined above, A and B can together form adicarboxylic anhydride group. The dicarboxylic anhydride group isreadily converted to two carboxyl groups by simple acid hydrolysis. Theolefin, AHC═CH₂, is a terminally unsaturated alkenoic acid representedby CH₂═CH—(C_(x)H_(2x))—COOH. The alkylene group bridging the vinyl andthe carboxyl groups can have from 1 to 24 carbon atoms or it can beabsent, and such alkylene group when present can be a straight chaingroup or branched chain. The useful acids are alkenoic acids of 3 to 20carbon atoms wherein the olefinic group is a terminal group.Representative but nonlimiting examples of alkenoic acids with aterminal olefinic group include acrylic acid, 3-butenoic acid,4-pentenoic acid, 5-hexenoic acid, 6-heptenoic acid, 7-octenoic acid,8-nonenoic acid, 9-decenoic acid, 10-undecenoic acid, 11-dodenoic acid,13-tetradecenoic acid, 15-hexadecenoic acid, 17-octadecenoic acid aswell as branched chain alkenoic acids with terminal olefinic groups suchas 2-ethyl-4-pentenoic acid, 2,2-dimethyl-4-pentenoic acid,3-ethyl-6-heptenoic acid, 2-ethyl-6-heptenoic acid,2,2-dimethyl-6-heptenoic acid, and the like. It should be understoodthat a mixture of alkenoic acids can be used.

The reaction leading to polysulfone formation is the art-knownfree-radical polymerization process. Nearly all types of radicalinitiators are effective in initiaing polysulfone formation. Radicalinitiators such as oxygen, ozonides, t-butylperoxy-pivalate, hydrogenperoxide, ascaridole, cumene peroxide, benzoyl peroxide,azobisisobutyronitrile are examples of some of the useful initiators.Free-radicals are generated from such radical initiators eitherthermally and/or by light activation in the presence of a mixture ofsulfur dioxide and 1-alkene. The polymerization can be carried out inliquid phase, conveniently in a solvent such as benzene, toluene orxylene to facilitate the reaction. In one aspect of this invention,ortho-xylene (“o-xylene”) is the solvent employed. Such solvent can beremoved, e.g., by distillation, if desired, but it is generally more theconvenient to use the polysulfone copolymer as a concentrate in suchsolvent. Generally, it is typical to use an excess of sulfur dioxidesince any unreacted sulfur dioxide is readily removed as by passingnitrogen gas into the polymer solution. An exess of 1-alkene can beused, however, and the excess subsequently removed as by distillation.

Using ortho-xylene has several advantages. For example, the use ofo-xylene as a solvent leads to increased conductivity, an increase ofapproximately 15% was observed when o-xylene was used (See Tables I andII, infra.) Ortho-xylene also facilitates the removal of toxins, e.g.,ethyl benzene. One also observes an increase in flash point usingo-xylene, as compared to tolene. This is mainly due to the difference inthe flash points between o-xylene (86° C.) and Toluene (40° C.) TABLE IComparison of the conductivity enhancement of a Static Dissipaterformulation where the poly Sulfone polymer in the formulation wasprepared in o-xylene, to that which was prepared in Toluene. FormulationConductivity pS/m Conductivity pS/m 1 PSI w/o-xylene 369 425 2 PSIw/o-xylene 342 388 3 PSI w/toluene 303 345

TABLE II Conductivity of a Static Dissipater formulations where the polySulfone polymer in the formulation was prepared in Toluene. FormulationConductivity 1 361 pS/m 2 338 pS/m 3 287 pS/m 4 347 pS/m 5 296 pS/m 6274 pS/m 7 272 pS/m 8 242 pS/m 9 300 pS/m

The particular ratio of 1-alkene to sulfur dioxide appears to beimmaterial since the resultant polysulfone copolymer contains 1-alkeneand sulfur dioxide in 1:1 molar ratio regardless of the particular ratioused. However, for efficiency in utilization of the reactants and of theequipment, a slight excess of sulfur dioxide is often employed. Thepolymerization can be carried out at atmospheric or super-atmosphericpressures, the polymerization reaction being independent of thepressure. The polymerization temperature can be any convenienttemperature below the ceiling temperature of the particular 1-alkeneemployed. Ceiling temperature is the temperature at which the rates ofpolymerization and depolymerization are equal so that no polymerformation takes place. The above mention “Encyclopedia of PolymerScience and Technology” on page 466 lists ceiling temperatures forvarious 1-alkenes. Generally, the convenient polymerization temperaturerange is from about 0° to about 50° C.

The Polymeric Polyamines:

The polyamine component of the antistatic composition of the presentinvention is a polymeric reaction product of epichlorohydrin with analiphatic primary monoamine or N-aliphatic hydrocarbyl alkylene diamine.The polymeric reaction products are prepared by heating an amine witheipchlorohydrin in the molar proportions of from about 1:1-1.5 in thetemperature range of about 50° to about 100° C. Generally, withaliphatic monoamines, R¹NH₂, the molar ratio is about 1:1. The initialreaction product is believed to be an addition product as illustratedbelow with a primary momoamine, R¹NH₂,

The aminochlorohydrin (I) upon reaction with an inorganic base thenforms an aminoepoxide.

The aminoepoxide (II), which contains a reactive epoxide group and areactive amino-hydrogen, undergoes polymerization to provide a polymericmaterial containing several amino groups. The ratio of epichlorohydrinto amine and the reaction temperature used are such that the polymericreaction product contains from 1 to 20 recurring units derived from theaminoepoxide represented by II.

The polymeric reaction product derived from epichlorohydrin and analiphatic primary monoamine as defined is represented by subgenericformula (A),

where a is an integer from 1 to 20 and x is an integer of 1 to 2.

The aliphatic primary monoamines that can be used to prepare thepolymeric reaction products with epichlorohydrin can be straight chainor branched chain and include, inter alia, octylamine, nonylamine,decylamine, undecylamine, dodecylamine, tridedecylamine, tetadecylamine,pentadecylamine, hexadecylamine, heptadecylamine, octdadecylamine,nonadecylamine, eicosylamine, heneicosylamine, docosylamine,tricosylamine, tetracosylamine and the corresponding alkenyl analogs.The aliphatic primary amine should have at least about 4 carbon atoms,in one aspect, about 12 to 24 carbon atoms to provide polymeric reactionproducts of sufficient solubility in hydrocarbon fuels. While aliphaticprimary amines containing more than about 24 carbon atoms are useful,such amines are of limited availability.

Mixtures of aliphatic primary amines can also be used, and are typicalsince mixtures of primary amines derived from tall oil, tallow, soybeanoil, coconut oil, cotton seed oil and other oils of vegetable and animalorigin are commercially available and at lower cost than individualamines. The above mixtures of amines generally contain alkyl and alkenylamines of from about 12 to 18 carbon atoms, although sometimes anindividual amine mixture, depending upon the source, contains smallamounts of primary amines having fewer or more carbon atoms. An exampleof a commercially available mixture of primary monoamines ishydrogenated tallow amine which contains predominantly hexadecyl- andoctadecylamines with smaller amounts of tetradecylamine.

When the amine reacted with epichlorohydrin is anN-hydrocarbylalkyl-enediamine as defined, the polymeric reaction productis represented by subgeneric formula (B),

where R¹ is an aliphatic hydrocarbyl group of 4 to 24 carbon atoms, R²is an alkylene group of 2 to 6 carbon atoms, b and c are integers of 0to 20 and b+c is an integer of 2 to 20 and x is 1 to 2.

In the reaction of epichlorohydrin with an N-aliphatichydrocarbylalkyl-enediamine, it is believed (because of the knowngreater reactivity of primary amino hydrogen over secondary aminohydrogen) that the initially formed aminochlorohydrin is of the formula

and the subsequently formed aminoepoxide is of the formula

When IIa undergoes further condensation, the recurring units in theproduct may be

or both, since (IIa) contains two reactive secondary aminohydrogens.Thus, in subgeneric formula (B), above, b is from 0 to 20, c is from 0to 20 and b+c is from 2 to 20.

Illustrative examples of useful N-aliphatic hydrocarbyl alkylenediamines include, but not limited to, N-octyl, N-nonyl, N-decyl,N-undecyl, N-dodecyl, N-tridecyl, N-tetradecyl, N-pentadecyl,N-hexadecyl, N-heptadecyl, N-octadecyl, N-nonadecyl, N-eicosyl,N-uneicosyl, N-docosyl, N-tricosyl, N-tetracosyl, as well as thecorresponding N-alkenyl derivatives of ethylenediamine,propylenediamine, butylenediamine, pentylenediamine and hexylenediamine.In one aspect, the N-aliphatic hydrocarbyl-alkylenediamine isN-aliphatic hydrocarbyl-1,3-propylenediamine. The N-aliphatichydrocarbyl-1,3-propylenediamines are commercially available and arereadily prepared from aliphatic primary monoamines such as thosedescribed above by cyanoethylation with acrylonitrile and hydrogenationof the cyanoethylated amine. Mixtures of N-aliphatichydrocarbyl-1,3-propylenediamines can also be advantageously used. Atypical mixture is N-tallow-1,3-propylenediamine which is commerciallyavailable as “Duomeen T” wherein “tallow” represents predominantlymixtures of alkyl and alkenyl groups of 16 to 18 carbon atoms which cancontain small amounts of alkyl and alkenyl groups of 14 carbon atoms.

The reaction between the amines (as defined) and epichlorohydrin isadvantageously carried out in the presence of a solvent such as benzene,toluene, xylene, ortho-xylene, or other higher boiling mixtures ofaromatic solvents, such as Aromatic 100 or Aromatic 150 which can alsocontain some hydroxylic component such as ethanol, propanol, butanol andthe like.

After the initial reaction between the amine and epichlorohydrin to forman aminochlorohydrin intermediate as illustrated above by Products I andIa, the reaction mass is treated with an inorganic base, such as sodium,potassium or lithium hydroxide, to form an aminoepoxide as representedby Products II and IIa above, which under continued heating undergoespolymerization to yield the desired product represented above by thegeneric formula and subgenerics A and B. Inorganic chloride formed inthe reaction is removed by filtration. The solvent used to facilitatethe reaction can be removed if desired, e.g., by distillation, butgenerally it is more convenient to use the polymeric polyamine as asolution.

The above-described reactions of epichlorohydrin with amines to formpolymeric products are well known and find extensive use in epoxideresin technology (cf. “Epoxy Resins”, Henry Lee and Kris Neville, TheMcGraw-Hill Book Co., 1957, the entire teaching of which is incorporatedherein by reference). The polymeric reaction products of epichlorohydrinand amines are complex mixtures but it is believed that the aboveformulas of the polymeric polyamines fairly represent the compositionand structures that are obtained.

The normally liquid hydrocarbon fuels to which the additives are addedto render such hydrocarbon fuels electrically conductive are thoseboiling in the range of about 20° to about 375° C. and include suchcommonly designated fuels as aviation gasoline, motor gasoline, jetfuels, naphtha, kerosene, diesel fuel and distillate burner fuel oil.The additive composition can be added in any conventional manner. Eachindividual component of the composition can be added to the hydrocarbonfuel separately or the composition can be added as a simple mixture oras a solution in a solvent, such as benzene, toluene, xylene, o-xylene,isopropanol, cyclohexane, Aromatic 100 and Aromatic 150 fuel oil, or ina mixture of such solvents. It is convenient to prepare both thepolysulfone copolymer and the polymeric polyamine in a solvent, such asone or more of those mentioned above. Thus, it is typical to use suchsolutions of polysulfone and polymeric polyamine and to combine them.The combination, which can be termed a concentrate, can then be added tothe hydrocarbon fuel. Such concentrate conveniently contains from about1 to 40% by weight of polysulfone copolymer, from about 1 to about 40%by weight of polymeric polyamine and from about 20 to 98% by weight of asolvent or a mixture thereof as described. In one aspect, theconcentrate will contain from about 5 to 25% by weight of polysulfonecopolymer, from about 5 to 25% by weight of polymeric polyamine and fromabout 50 to 90% by weight of solvent.

When formulating concentrates, it is typical that the polymericpolyamine be present as a salt, particularly a sulfonic acid salt, forimproved resistance to precipitate formation in storage. For example,when a concentrate as described comprising polymeric polyamine in thefree base form is stored at elevated temperatures of about 44° C. for aperiod of time of about 4 weeks, a small amount of precipitate sometimesforms. The presence of small amounts of precipitate in the concentrateshave little or no effect on the usefulness of the present compositionsas antistatic additives but are undesirable if only from an aestheticpoint of view. It has been found that strong acids such as hydrochloric,sulfuric or a sulfonic acid can be used to limit precipitate formationin the concentrates. Oil-soluble sulfonic acids are typical because theyeffectively inhibit precipitate formation without substantialdeleterious effect upon the electrical conductivity property of thecomposition. Any oil-soluble sulfonic acid such as an alkanesulfonicacid or an alkarysulfonic acid can be used. A useful sulfonic acid ispetroleum sulfonic acid resulting from treating oils with sulfuric acid.

Generally, the amount of sulfonic acid incorporated in the concentrateis an equivalent amount, that is, sufficient amount of sulfonic acid toneutralize all the amine groups of the polymeric polyamine, althoughlesser or greater than the equivalent amount can be used. Thus, one formof the concentrate of the present invention will contain from about 5 to25% by weight of polysulfone copolymer, from about 5 to 30% by weight ofpolymeric polyamines, from about 5 to 30% by weight of, say,dodecylbenzenesulfonic acid, and from about 20 to 85% by weight ofsolvent. Typically an equivalent amount of dodecylbenzenesulfonic acidor dinonylnaphthyl sulfonic acid is used.

When a three-component additive is employed (where a quaternary ammoniumcompound is the third component), the concentrate composition willcomprise, based on total weight of the composition: from about 5 to 25%of polysulfone, from about 5 to 25% of polyamine, from about 0.5 to 5%of quaternary ammonium compound, from about 5 to 25% of a sulfonic acid,say, dodecylbenzene sulfonic acid, and from about 20 to 84.5% ofsolvent.

The utility of the present invention composition as a highly effectiveantistatic additive for hydrocarbon fuels is demonstrated by the factthat the incorporation into hydrocarbon fuels of as little as 0.00003%by weight (0.3 part per million, ppm) of polysulfone copolymer and0.00002% by weight (0.2 ppm) of polymeric polyamine is sufficient, innearly all hydrocarbon fuels investigated, to provide electricalconductives of at least 100 C.U. (conductivity units). In certainresponsive fuels, as little as 0.0000018 weight % (0.018 ppm)polysulfone copolymer and 0.0000013 weight % (0.013 ppm) polymericpolyamine provide a conductivity of at least 100 C.U. Thus, the presentinvention provides a highly effective ashless antistatic additivecomposition which confers increased electrical conductivity tohydrocarbon fuels at very low usage levels.

The antistatic effectiveness of the present invention composition isunexpected as the polysulfone product prepared in o-xylene and thecorrespondent composition derived from said polysulfone is superior to asimilar composition derived from polysulfone prepared from toluene.

The hydrocarbon fuels into which the present composition is incorporatedexhibit satisfactory water interaction properties as evidenced bysatisfactory results in the water separation test according to ASTMD-2250-66T. The hydrocarbon fuel composition containing the compositionof the invention can also contain conventional additives used inhydrocarbon fuels such as antiknock compounds, antioxidants, corrosioninhibitors, metal deactivators, rust preventatives, dyes, anti-icingagents and the like.

The polysulfones, and poly amines evaluated in the present inventionwere prepared according to procedures outlined in U.S. Pat. No.3,917,466. The examples cited therein are not intended to be a limit ofthe scope of the invention.

Another embodiment of the present invention is directed to a fuel oilcomposition. This fuel oil composition can comprise a suitable fuel oilcomponent and a suitable additive component. In one aspect, thecomposition comprises from about 99.99% fuel and about 0.01% additive toabout 99.9999% fuel to about 0.0001% additive. In one aspect, a suitableadditive includes those described herein. The fuel oil can be apetroleum-based fuel oil, suitably a gasoline or middle distillate fueloil. The fuel oils can comprise atmospheric or vacuum distillate,contain cracked gas oil in or a blend of any proportion of straight runor thermally or catalytically cracked distillates, and in many cases arehydrogen-treated or otherwise processed to improve properties.

Gasolines are low boiling mixtures of aliphatic, olefinic, and aromatichydrocarbons, and optionally alcohols or other oxygenated components,boiling in the range from room temperature up to 225° C. Other fuel oilsare kerosine, jet fuels, diesel fuel oils and home heating fuel oils(such as, middle distillate heating fuels), generally having flashpoints greater than 380° C. These fuels are higher boiling mixtures ofaliphatic, olefinic, and aromatic hydrocarbons having a boiling point upto 350° C.

Conductivity of fuels and solvents comprising static dissipators arecommonly measured using ASTM D 2624 or IP 274, a technically equivalentmethod. See, ASTM D 2624-02, the entire teaching of which isincorporated herein by reference. For comparative purposes, compositionscan be tested according to the method described in ASTM in fuels, or ina standard solvent such as Isopar M. Isopar M is a high-flash solventmarketed by Exxon Mobil and is highly paraffinic. Results from testingin this solvent are directionally similar to those obtained in fuelssuch as motor gasoline, aviation gasoline, aviation turbine fuel, dieselfuels of various sulfur contents, and home heating fuels.

Although the invention has been described with respect to variousembodiments, it should be realized this invention is also capable of awide variety of further and other embodiments within the spirit andscope of the appended claims.

1. An antistatic additive composition for hydrocarbon fuels comprising,based on total weight, i. from about 1 to 50 percent of polysulfone, ii.from about 1 to 50 percent of polymeric polyamine, iii. from about 1 to30 percent of oil-soluble sulfonic acid, and iv. from about 3 to 97percent of solvent, said polysulfone of (i) comprising about 50 molpercent of units from sulfur dioxide, about 40 to 50 mol percent ofunits derived from one or more 1-alkenes each having from about 4 to 24carbon atoms, and from about 0 to 10 mol percent of units derived froman olefinic compound having the formula ACH═CHB wherein A is a grouphaving the formula —C_(x)H_(2x))—COOH wherein x is from about 0 to about17, and B is hydrogen or carboxyl, with the proviso that when B iscarboxyl, x is 0, and wherein A and B together can be a dicarboxylicanhydride group, said polymeric polyamine of (ii) having the formula

wherein R¹ is an aliphatic hydrocarbyl group of 8 to 24 carbon atoms, R²is an alkylene group of 2 to 6 carbon atoms, R is R¹, or, an N-aliphatichydrocarbyl alkylene group of the formula R¹NHR², a is an integer of 0to 20, b is an integer of 0 to 20, c is an integer of 0 to 20, and x isan integer of 1 to 2, with the proviso that when R is R¹ then a is aninteger of 2 to 20 and b=c=0, and when R is R¹NH—R² then a is 0 and b+cis an integer of 2 to 20, said oil-soluble sulfonic acid of (iii) beingdodecylbenzenesulfonic acid, and said solvent of (iv) beingortho-xylene.
 2. The composition of claim 1, wherein said polysulfonehas an molecular weight ranging from about 10,000, to about 1,500,000amu.
 3. The composition of claim 1, wherein said polysulfone is selectedfrom the group consisting of 1-hexene, 1-heptene, 1-octene, 1-nonene,1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene,1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonodecene,1-eicosene, 1-heneicosene, 1-docosene, 1-tricosene, and 1-tetracosene.4. The composition of claim 3, wherein said polysulfone is 1-decene. 5.The composition of claim 1, wherein said polymeric polyamine is apolymeric reaction product of epichlorohydrin with an aliphatic primarymonoamine or N-aliphatic hydrocarbyl alkylene diamine.
 6. Thecomposition of claim 5, wherein said aliphatic primary monoamine isselected from the group consisting of octylamine, nonylamine,decylamine, undecylamine, dodecylamine, tridedecylamine, tetadecylamine,pentadecylamine, hexadecylamine, heptadecylamine, octdadecylamine,nonadecylamine, eicosylamine, heneicosylamine, docosylamine,tricosylamine, and tetracosylamine.
 7. The composition of claim 5,wherein said N-aliphatic hydrocarbyl alkylene diamine is selected fromthe group consisting of N-octyl, N-nonyl, N-decyl, N-undecyl, N-dodecyl,N-tridecyl, N-tetradecyl, N-pentadecyl, N-hexadecyl, N-heptadecyl,N-octadecyl, N-nonadecyl, N-eicosyl, N-uneicosyl, N-docosyl, N-tricosyl,N-tetracosyl, as well as the corresponding N-alkenyl derivatives ofethylenediamine, propylenediamine, butylenediamine, pentylenediamine,and hexylenediamine
 8. The composition of claim 1, wherein a weightration of said polysulfone to said polyamine ranges from about 100:1 toabout 1:100.
 9. The composition of claim 1, wherein a weight ration ofsaid polysulfone to said polyamine ranges from about 50:1 to about 1:1.10. The composition of claim 1, wherein a weight ration of saidpolysulfone to said polyamine ranges from about 20:1 to about 1:1. 11.The composition of claim 1, wherein said sulfonic acid is either a monoor di sulfonate of alkyl benzene.
 12. The composition of claim 11,wherein said sulfonic acid is either dodecylbenzene sulfonic acid ordinonylnaphthyl sulfonic acid.
 13. A hydrocarbon fuel boiling range offrom about 200 to about 375° C. having from about 0.01 ppm to about 40ppm of said composition defined in claim
 1. 14. An antistatic additivecomposition comprising, based on total weight, i. from about 1 to 50percent of polysulfone, ii. from about 1 to 50 percent of polymericpolyamine, and iii. from about 3 to 97 percent of solvent, saidpolysulfone of (i) comprising about 50 mole percent of units from sulfurdioxide, about 40 to 50 percent of units derived from one or more1-alkenes each having from about 4 to 24 carbon atoms, and from about 0to 10 mol percent of units derived from an olefinic compound having theformula ACH═CHB wherein A is a group having the formula—C_(x)H_(2x))—COOH wherein x is from 0 to about 17, and B is hydrogen orcarboxyl, with the proviso that when B is carboxyl, x is 0, and whereinA and B together can be a dicarboxylic anhydride group, said polymericpolyamine of (ii) having the formula

wherein R¹ is an aliphatic hydrocarbyl group of 8 to 24 carbon atoms, R²is an alkylene group of 2 to 6 carbon atoms, R is R¹, or, an N-aliphatichydrocarbyl alkylene group of the formula R¹NHR², a is an integer of 0to 20, b is an integer of 0 to 20, c is an integer of 0 to 20, and x isan integer of 1 to 2, with the proviso that when R is R¹ then a is aninteger of 2 to 20 and b=c=0, when R is R¹NH—R² then a is 0 and b+c isan integer of 2 to 20, and said solvent of (iii) being ortho-xylene. 15.An antistatic additive composition comprising, based o total weight, i.from about 1 to 50 percent of polysulfone, ii. from about 1 to 50percent of polyamine, iii. from about 0.5 to 5 percent of quaternaryammonium compound, iv. from about 1 to 30 percent of oil-solublesulfonic acid, and v. from about 3 to 97 percent of solvent, saidpolysulfone of (i) comprising about 50 mol percent of units derived fromsulfur dioxide, from about 40 to 50 mol percent of units derived form1-alkene of 4 to 24 carbon atoms and 0 to about 10 mol percent of unitsderived from an olefin having the formula, ACH═CHB, wherein A is a grouphaving the formula —(C_(x)H_(2x))—COOH wherein x is from 0 to about 17,and B is hydrogen or carboxyl, with the proviso that when B is carboxyl,x is 0, and wherein A and B together can be a dicarboxylic anhydridegroup, said polyamine of (ii) having the formula

wherein R¹ is an aliphatic hydrocarbyl group of 8 to 24 carbon atoms, R²is an alkylene group of 2 to 6 carbon atoms, R is R¹, or, an N-aliphatichydrocarbyl alkylene group of the formula R¹NHR², a is an integer of 0to 20, b is an integer of 0 to 20, c is an integer of 0 to 20, and x isan integer of 1 to 2, with the proviso that when R is R¹ then a is aninteger of 2 to 20 and b=c=0, and when R is R¹NH—R² then a is 0 and b+cis an integer of 2 to 20, the quaternary ammonium compound of (iii)having the formula

wherein Alk¹ and Alk² are the same or different alkyl groups having from1 to 22 carbon atoms, Alk³ is selected from the group consisting ofalkyl groups of 1 to 22 carbon atoms and

where Alk³ is hydrogen or methyl and n is 1 to 20, Alk⁴ is selected fromthe group consisting of (a) an alkyl group having 1 to 22 carbon atoms,(b) an aralkyl group having from 7 to 22 carbon atoms, (c) a

group as defined above, (d) a

group, wherein Alk⁶ and Alk⁷ are the same or different alkyl groupshaving from 11 to 19 carbon atoms, and (e) an —Alk⁸—CO₂ group whereinAlk⁸ is a hydrocarbyl group having from 1 to 17 carbon atoms, with theproviso that when Alk¹, Alk², Alk³ and Alk⁴ are each alkyl groups, atleast one of them is an alkyl group having at least 8 carbon atoms, A isan anion, z is 0 or 1, z is 0 when Alk⁴ is (d) or (e), and y is at least1, y is equal to the ionic valence of anion A when z is 1, saidcomposition comprises, in combination therewith, said oil-solublesulfonic acid of (iv) being dodecylbenzenesulfonic acid, and saidsolvent of (v) being ortho-xylene.
 16. The composition of claim 15,wherein said quaternary ammonium is dicocodimethyl ammonium nitrite. 17.A composition comprising a major proportion of a suitable fuel oil and aminor portion of a suitable additive.
 18. The composition of claim 17,wherein said suitable fuel oil is selected from the group consisting ofa petroleum-based fuel, kerosene, jet fuel oil, middle distillateheating oils, and diesel fuel oil.
 19. The composition of claim 18,wherein said petroleum-based fuel is a gasoline or middle distillatefuel oil.
 20. The composition of claim 17, wherein said suitableadditive is an additive defined by claim 1.